With the 9c/28 and c/98 speeds, nothing makes them magic numbers in CGOL. The long-term behavior of a life-like CA, even with a tiny change, is significantly different than that of CGOL (e.g., run the pi heptomino to completion in B3/S238). There is really no predictive power, no way to say that since something has one behavior in one rule, that it should have similar behavior in another. For a given pattern, either the difference doesn't come up, so the behavior is exactly the same, or it does, in which case there's no way to recover the original behavior. The ships above are both in the latter category.

I think an automated spaceship search would choke so badly at period 28 or 98 that there's no point in ever running one. Instead, statistically there are tons of more reachable spaceships at smaller periods, just barely past the edge of current technology/patience. That includes knightships, which moebius's "knight" programs have been trying to make more attainable.

There's also a big complexity difference between naturally occurring patterns and those found by search programs.

THOUGHT: There might be a way to set up a soup searcher so that it doesn't have such a predisposition against slow spaceships. Currently, any spaceship that forms would have to do so at the edge of the reaction envelope, facing the right direction, and then get out of the way of any other active reactions (many of which propagate close to c/2). However, it's relatively easy to check for a given object whether that object is an oscillator or spaceship of any period < N for some large enough N. At the cost of speed, then, one could take snapshots of the soup prior to it stabilizing and do censuses of active objects as well as ash. There would have to be some very smart rejection to avoid wasting all of the time on methuselahs, and also some very smart code to determine which active objects deserve to be treated as separate for a given snapshot. But the time/effort cost could pay off because this method would have a much higher chance of identifying temporary spaceships in soups.

One possible procedure would be to put each object in its own universe and run that to stabilization, knowing beforehand the ash products of most methuselahs, and using the same analysis apgsearch variants use for oscillators, spaceships and linear+ growth. However, this is dreadfully slow, and if we use a snapshot every 50 gens (seems potentially reasonable), then long-lived soups could mean we look at hundreds of objects hundreds of times, far outweighing the potential gain.

It just makes me sad to think of a loafer or a tiny c/18 ship or something crashing into a blinker in the middle of a forgotten apgnano search..

biggiemac wrote:It just makes me sad to think of a loafer or a tiny c/18 ship or something crashing into a blinker in the middle of a forgotten apgnano search..

Then why not make it delete known stationary lifes that might get in the way? And then again, vital things like the loaf pushed by a loafer or the block hauled by the copperhead would get removed. So we could make objects close to a reaction not get destroyed, but that reaction may well be a ship that it's about to bugger over...

What may be worth considering, however, is a search program that evades these errors mostly, for example: taking objects found in soups and running those to completion, and if they happen to be a 45786473457c/9007199254740992 orthogonal ship or something, they get displayed under results (and you get displayed alongside your discovery in the Life community).

Back on topic: simply because a ship in a similar rule set does not function does not necessarily mean it cannot be tweaked or a similar ship cannot be built. For example, the c/98 uses boats - which are stable in both 3/23 and 36/23. Assuming a reaction is found which is similar to the one in the ship, or any reaction in general is found using boats or any other still life, a ship could be patched together which runs at a whole new speed. I doubt any of that came out right, but hopefully you understand what I was basically saying.

Of course, this is not always the case, as in this compact orthogonal c/5648:

muzik wrote:Back on topic: simply because a ship in a similar rule set does not function does not necessarily mean it cannot be tweaked or a similar ship cannot be built. For example, the c/98 uses boats - which are stable in both 3/23 and 36/23. Assuming a reaction is found which is similar to the one in the ship, or any reaction in general is found using boats or any other still life, a ship could be patched together which runs at a whole new speed.

I think I understand, but I have to disagree -- in practice, anyway. For example, there's no particular point in looking for a c/98 spaceship in B3/S23 with a pair of trailing boats in it at those locations.

Certainly it's theoretically possible that such a spaceship exists, but it's no more likely than a spaceship with any other stable back end, and no more likely than a c/88 spaceship, or any other nearby speed.

The fact that the c/98 happens to work is an emergent property of the B36/S23 rule. The 6-neighbor birth rule is invoked in that active reaction -- here, there and everywhere. It's in there at far too low a level for it to be possible to just pull out all those reactions and replace them with something else, keeping "everything else the same".

In general, a pattern in one rule just plain doesn't give any information about behavior in another rule, unless it can be shown that a birth or survival rule with some neighbor count is never used in a particular reaction. In that case, the exact same pattern will trivially work in multiple rules, as biggiemac mentioned at the top of his message. Even tiny changes in the rule will tend to cause huge changes in the emergent patterns that appear.

... Now, you could build a replicator-metacell in Conway's Life that emulates HighLife, and then you could build a meta-c/98 spaceship and it would work fine -- but that's definitely cheating.

dvgrn wrote:... Now, you could build a replicator-metacell in Conway's Life that emulates HighLife, and then you could build a meta-c/98 spaceship and it would work fine -- but that's definitely cheating.

And would not count because the cells aren't actually moving.

Of course, small ships that exist in rules similar to regular Life obviously won't work in regular Life, but since the rules are similar we can at least assume that there are small ships of exotic speeds not yet seen in the real thing. I know I'm a noob at the whole cellular automata thing, and am stating the obvious all the time, but basically, since strange speeds exist for small patterns in similar rules, this means that it is highly likely that there may be something like a shockingly small 18c/231 ship right behind the door. It's highly unlikely that these will be discovered way too soon unless an interesting and intriguing reaction is found, since most attention seems to be focused on speeds like c/8, c/9 and 3c/7.

On that note, I've been considering setting up a thread containing notable partials for undiscovered, high priority speeds, for research to be conducted on. (I could also add in a few small ships of these speeds from other rules to display how fast they will move, although this might not be way too helpful.)

Last edited by muzik on March 9th, 2016, 4:53 pm, edited 1 time in total.

dvgrn wrote:... Now, you could build a replicator-metacell in Conway's Life that emulates HighLife, and then you could build a meta-c/98 spaceship and it would work fine -- but that's definitely cheating.

And would not count because the cells aren't actually moving.

Dave meant metacells that do not need medium, thus "replicator-metacell". They are already technologically possible, but no explicit example has been constructed yet. They would count.

muzik wrote:I know I'm a noob at the whole cellular automata thing, and am stating the obvious all the time, but basically, since strange speeds exist for small patterns in similar rules, this means that it is highly likely that there may be something like a shockingly small 18c/23 ship right behind the door.

It's not only unlikely, it certainly does not exist.

muzik wrote:On that note, I've been considering setting up a thread containing notable partials for undiscovered, high priority speeds, for research to be conducted on.

There are already threads that are dedicated to spaceship partials. Is there really a need to create a new one?

muzik wrote:I know I'm a noob at the whole cellular automata thing, and am stating the obvious all the time, but basically, since strange speeds exist for small patterns in similar rules, this means that it is highly likely that there may be something like a shockingly small 18c/23 ship right behind the door.

It's not only unlikely, it certainly does not exist.

I definitely typed in 231. I hate this keyboard

codeholic wrote:

muzik wrote:On that note, I've been considering setting up a thread containing notable partials for undiscovered, high priority speeds, for research to be conducted on.

There are already threads that are dedicated to spaceship partials. Is there really a need to create a new one?

It would most likely be more convenient to have them in one thread than have to rake through hundreds of random, unrelated posts to find them.

muzik wrote:Would it be possible to make a ship using a queen bee, and a reaction to "push" (or pull) it ahead?

Might be. Doesn't sound any likelier than "a ship using a ____, and a reaction to move it" for any number of other objects -- pi, century, dove, wing, LOM, etc., etc. If you have an actual example where an object and a push/pull reaction work together to move the object at some particular speed, then you can maybe make a guess about whether it can be turned into a spaceship. Without a promising start like that, this kind of question really just seems like vague hand-waving.

If you just put a queen bee in to WLS or a custom zfind or whatever, and specify that you want the queen bee to have moved N cells in T ticks, then it's always possible that you might find a solution, if you specify the constraints just right. However, for any specific search, the odds of success are (I think) probably very very low.

This is something that is hard to understand from people just talking about it. Unfortunately, your best bet at developing a sense of likely vs. improbable is to go ahead and run multi-day searches for a while, and have them not return anything (!).

This will probably be due to trying to search in too large a search space. It's very easy to set up WLS with so many unknown cells that you're effectively searching for a needle in a haystack the size of Jupiter. The needle is probably in there somewhere, but that doesn't mean that your search is going to find it.

So then to fix the Jupiter-sized-haystack problem need to add more or less arbitrary constraints. Once you've reduced the search space to a reasonable size, and then at least the search will finish and you'll know whether or not there's an answer in that particular space.

Queen bees are symmetric, so that reduces the number of unknown cells by quite a bit -- but then again, they're pretty big and move around quite a bit, so that brings the unknown cell count up again. On balance I'm thinking it would be hard to set up a search for a magic queen-bee pusher, where the search would complete in a reasonable amount of time. But you're welcome to give it a try, of course!

Sorry if this was asked before, but I was wondering if it would be practical to use multiple layers of glider stream used to protect an object from stray gliders. It can also be used to detect whenever gliders hit the stream using the gaps it leaves behind. Here's a pattern to show what I mean:

I know that a glider might cause an explosion that could pass through the glider stream. To further protect the object, multiple layers of glider stream could be used and each one would be isolated. Maybe a different period of gun would be best. Maybe a different type of spaceship could be used instead.

Well, it could be interesting for a memory circuit thing. There could also maybe be another glider gun farther down the line which annhialates with the other glider stream, and a disruption further up which would cancel the gliders could allow a few of those to pass through.

Not sure, but that might have been a result of the recent-ish discussion of the H' object? If so it'll be in one of the posts in the 'The Hunting of the New Herschel Conduits' thread from a few months ago.

I find it very interesting that the two earliest known simple guns (p30 GGG and p46 twin bees gun) both have comparably simple but unrelated guns at multiples of their period, 30 x 4 = 120 for the Simkin gun and 46 * 4 = 184 for this gun. Furthermore, while the originals are based upon shuttles, the latter are based upon Herschel conduits.

Also the p138 gun based on Gabriel Nivasch's p138 is 46 x 3. Many a strange coincidence.

Would it be possible to search for a small glider gun of period < 20 by searching for oscillators which emit gliders as "sparks"? As in, a small billiard-ish oscillator-like thing emitting gliders, akin to oscillators emitting large sparks.

The term is used in this forum and in a couple articles in the wiki, but I don't see a definition anywhere.

It's odd that the definition wasn't copied from the Life Lexicon, since that's where a lot of other LifeWiki definitions got their start.

See the Life Lexicon definition for starters. Drat, there's another Lexicon entry that needs updating, since it talks only about the Caterpillar, and these days we also have waterbear and now Caterloopillar helices.